Method of finishing wood surfaces



Oct. 13, 1959 J. P.'NoRR|s METHOD oF FINISHING woon suRFAcEs 5 Sheets-Sheet 1 Filed Dec. 31, v195'7 Oct. 13, 1959 J. P. NoRRls METHOD oF FINIsl-xmc woon suRFAcEs 3 Sheets-Sheet 2 Filed Dec. 3l, 1957 wil i -|-|.l.

ATTORNEYS Oct. 13, 1959 J. P. NoRRls METHOD oF FINISHING woon sURFAcEs 3 Sheets-Sheet 3 Filed Dec. 31, 1957 IVENTOR BY Wg Mfg Anom 2,908,590,` METHOD oF FINISHING Woon SURFACES James P. Norris, Louisville, Ky., `assgnorto 4Wood- AMosaic Corp., Louisville, Ky., a'c'oiporation oi." Kentucky e "ift je.; i Applicaties December` 3119s7sefialNe. 706,465

8 Claims. (Cl. 117-64) The present invention relates in general to factory finishing of wood flooring, andmore particularly to the manufacture of factory finished wood ooring blocks.

Heretofore,` processes have been developed for finishing wood flooring, either in block or strip form, or par.- quetry type pattern flooring in the factory so that no additional finishing operation is required when the flooring'is laid. `One of such finishing processes involved the applicationto the wood of ya finishing composition'that rapidly penetrates the wood, as distinguished from a finish that merely coats the surface, then rubbing or wiping the composition, and subjecting the treated wood to curing or air drying for a period of time. A filler composition was then applied and rubbed or brushed, and the flooring was stacked to dry for several hours. After drying, a wax `or polishing composition was appliedand the composition was polished to a high gloss. The necessity for extended curing or air drying in this process presented serious problems, in that extensive storage space and excessive handling was required for the flooring during the drying `period and the substantial drying periods lengthened considerably the production time.

v Much effort has been devoted to development of processes for drastically reducing the time required to produce an improved factory finish on flooring. Many of these require extensive machinery installations and result in finishes, having something less than the desired durability orother properties.

An object of the present invention is the provision of a novel continuous process of nishing block ooring and the like which eliminates interruption in the finishing line and conditions the blocks for immediate inspection and packaging at the end of the finishing line.

Another object of the presentinvention is the provision of a novel continuous process of providing a hard and lasting factory finish on block wood ooring, wherein the wood `is coated with a deeply penetrating sealer composition and a filler composition which are rapidly dried in a manner permitting completion of the entire finishing operation in a period of minutes with high utilization of finishing materials, i

Another object of the present invention is the provision of a novel improved continuous process of providing a composite factory finish on wood block flooring, wherein the wood is coated with a deeply penetrating vinyl-base sealer composition to provide a good adhesive platform for further finishing and to improve moistureand cold check resistance, heating to dry and cure sealer, then a filler composition being worked into the pores and open grain surface to impart color and produce a smooth uni form iinish, drying the filler and polishing to produce a final nish with more lustre and depth, andfinally superimposing over the cured insoluble iillercoat a reactive resin mixtureformulated to produce a topcoat film' of high solid contentand extremely tough and wear resistant properties, and heating `to dry and cure this surface coat; all of which is rapidly processed in a novel manner permitting completion ofthe entire iinishingoperation, including inspection and packaging', in the heretofore unrealistic time of eleven (ll) minutes.

*Other objects, advantages and capabilities of the present invention will become apparent from the following detail description, taken in conjunction with the accompanying drawings-'showing one preferred form of the invention.

Inthe drawings: Figures la, 1b and 1c together represent a diagrammatic plan view of a finishing line for finishing wood i block flooring in accordance with the process ofthe 15 present invention.

Referring to the drawings, substantially square wood flooring blocks, indicated bythe reference ,character 10, 'which in the preferred exampleare of a commercially marketed type formed of a plurality of plys having tongues on two edges and mating grooves onthe other edges, are transferred to or deposited on the feed end of a pair of side by side endless conveyor belts 11, 12 from a hopper, feed conveyor, or other conventional supply facility for delivery through the finishing line. The conveyor belts `11, 12 are of the normal commercial construction of multiple plys of rubberized fabric with rough rubber sur# face for maximum traction, and are preferably of slightly smaller width than the blocks 10. For convenience in understanding certain details ofthe hereinafter described process, representative values of speed, temperatures'and the like willlbegiven for one preferred example. 'In the preferred example, the belts 11, 12 are driven at a speed to advance the blocks at a rate of 106 per minute. l

The blocks are advanced by the conveyor belts 11, 12 from the feed station, indicated generally by the reference character 13, through a sealer application station 14 where the upwardly facing surfaces of the blocks 410 are iirst brushed by aA driven cylinder brush 15 to cleanthe upwardly facing surfaces and are then advanced into contact with a sealer applying roll 16 which applies a wash coat sealer composition to the `adjacent surfaces of the blocks 10. The object of the wash coat sealer is to provide a goodv adhesive platform for further finishing through penetration of the wood substratum, to improve moisture and cold check resistance of the blocks and to harden the'nibs and raised wood fibres so they may be sanded off to assure a smooth, even surface for the filler application. f

The wash coat sealer is a lacquer type material which drys by evaporation of its solvent. Examples of this type Percent solids by weight Vinyl 'chloride-acetate resin l0-l2 Methyl-iso-butyl-ketone 22.5 Toluol 67.5

Pigments and dye-stuffs may be added if desired to obtain various colors."

In the example herein shown, the distanceralong the conveyor belts allocated to the wash coat sealer station may be six feet so that 4the blocks will occupy this station for a period of about seven seconds. Thereafter, the blocks are delivered througha flash station 17, which may be about ve feet long and require a travel time of five seconds, wherein the volatile wash coat sealer composition applied by the roll 16 will undergo rapid evaporation at approximately ambient temperature under the influence of forced air circulation by providing a hood and vent fan over the flash station 17.

After traversing the flash station 17 the block flooring enters aV sealer coat drying oven 18 ofthe hot air forced circulation type which may be approximately forty-nine and one-half feet long so that the flooring requires about sixty-five seconds to traverse the length of the oven 18. In the preferred example, the oven 18 has a temperature gradient of approximately 75 V F. to 150 F. to provide a gradual temperature exposure, so that the coated surface of the wood blocks, assuming they entery the oven 18 at a temperature of about 70 F., would have a temperature of about 110 F. at the exit end of the oven 18. The heat for the oven 18 to provide the desired temperature gradient may be derived from steam coils 19 located at the exit end of the oven, over which air -is forced to be heated and circulated through the oven by the fan 20.

After passage through the sealer coat drying oven 18, the blocks 10 traverse a cooling section 21 which may be about thirty-four feet long and have a traverse time of about fifty seconds. A series of Sanders 22 are located 'in the cooling section 21 near the exit end of the oven 18 for scuff sanding the coated surfaces of the blocks 10 to remove the nibs after the wash coat sealer application and before application of the ller. Ihe Sanders 22 may take the form of Minnesota Mining and Manufacturing Co. type P-G abrasive wheels which are arranged in pairs spaced longitudinally of the finishing line' axis, wherein the wheels are staggered transversely of this axis so that the rst pair of Wheels effect scuff sanding of one-half of each of the blocks arranged to one side -of the longitudinal medial axis of the block and the other pair of sander wheelssand the other half of each block. If special applications require spraying of some composition on to the wood blocks, a spray booth may conveniently be incorporated in the cooling section 21, in which case the blocks will betransferred from the rubber conveyor belts 11, 12 to chain belts for the duration of their travel through the spray booth and then transferred back to vrubber belts 11, 12. The surface temperature of the blocks will have been reduced to about 85 F. at the exit end of the cooling section '21. l

The blocks 10 then pass through a filler application station 23 which may be about six feet long and have a traverse time of about seven seconds, wherein a filler composition, having a heavy base and little solvent so that it is a highly viscous composition, s applied to the upper surface of the blocks 10 by an applicator roll 24 to roll an even coating of the filler on to the block surfaces. The roll 24 may, if desired, receive the coating composition from a transfer roll which transfers the composition from a trough roll to the roll 24, the transfer roll having spaced annular grooves in the surface thereof lying in plane normal to the roll axis to control the amount of composition applied to the blocks.

The function of the filler is to ll the open grain of the wood surface to produce a smooth uniform finish and to impart color to the finish. The filling material used in this process is made up of inert filling pigments, organic and inorganic pigments, organic dye-stuffs, vehicles and solvents formulated to provide proper consistency for wiping and padding into the open pores.

After rapid evaporation of solvents by forced air supply, padding, and brushing, the remaining filler solids are dried by solvent evaporation, oxidation, or chemical conversion to an insoluble film accelerated by catalysts and/or heat. This insoluble surface thus prevents the formation of bubbles or blistering through subsequent top coats.

A Asatisfactory filling composition to produceV after drying, a filled surface insoluble in subsequent coats is as follows:

Percent by weight Catalyst-5 to 10% toluene sulfonic acid based on urea formaldehyde solids. Reduced with VMP naptha as I required.

t Theller coatedrblocks 10 then pass into a ller padding and brushing section 25 wherein the-blocks first encounter two longitudinally spaced groups 26 and 27 of motor driven stroke padders, a temperature controlled forced air supply, schematically indicated at 28, being located immediately after each group of stroke padders 26 and 27 to maintain the ller at proper consistency for optimum padding. A pair of air-motor driven rotary padders 29 are also located within the section 2S immediately after the Vsecond group of stroke padders 27 to further pad the filler coated blocks -10 and removal of surplus filler and final cleaning of the filler coated y blocks is achieved by a pair of rotary cylindrical brushes 30, 31 which rotate on a horizontal axis and are set'at oppostely inclined angles to the axis of the finishing line. It will be appreciated that the filler, which is a very viscous composition, does not penetrate into the ywood blocks 10 to any appreciable extent due to its high viscosity and due to the fact that the surfaces of the wood blocks have already been sealed by the wash coat sealer composition. Y l

The wood blocks 10 then enter an infra-red heat oven 32 which is approximately thirty-one and one-half feet long and has a traverse time of about forty-four seconds,

type infra-red generators to provide a temperature gradient such that the wood blocks, which have a surface Itemperature of about F. when they enter the oven 32, leave the oven at a temperature of about F.

The wood blocks 10` then traverse a forced circulation A cooling section 33 of about twenty-four feet in length having a traverse time of about thirty-three seconds, `wherein the surface temperature of the wood blocks 10 is reduced to about 100 F.v at the exit end of the cooling section 33, and then enter a polishing and brushing section 34 involving a traverse time of about eighteen seconds.

In the polishing and brushing section 34, the blocks 10 are lirst polished by a Wide belt overhead sander 35 using a exiblerpaper or cloth backed endless abrasive belt ranging from 300 grit to as high as 400 grit. The

sander utilizes a resilient rubber covered contact drum which is driven by a motor and in turn drives the abrasive belt at a high rate of speed. It will be appreciated that the nibs on the surface of the blocks 10 were again raised and the surface was aggravated by the padding and brushing which occurred in the filler padding and brushing section 25. By polishing thesurface of the wood blocks after infra-red drying and cooling of the lller coating, a nish which is more uniform in color results, and a smoother final finish lwith more luster and depth results due to the polishing and removal of nibs, extraneous ller, dirt and dust immediately prior to top coat application. The sander 35 in the preferred embodiment is located seven feet from the exit end of the cooling section 33', so that a traverse time of aboutten seconds is required for the blocks to pass from the exit end ofthe cooling section 33 to the sander 3.5. With proper selection of vbelt abrasive and bond, feed speed and contact drurn pressure, the frictional heat generated by the abrasive belt is dissipated without causing pret. mature belt ll'ing'and burn' `g and uniform results are obtained. AY horizontal, cylindrical rotary brush 36 located transverse tothe axis of the nish line is also provided in the section 34 for removing surface dust from the wood surface generated by the sander 35.

At the end of the polishing and brushing section 34, theblocks are transferred from the belts 11, 12 to similar conveyor belts 37, 38 respectively moving at right angles'vto the belts 11, 12. Suitable xed plates 39 which are of smaller width than the blocks 10 are provided at the points of intersectionof the belts 11, 12 with the belts 37, 38 to receive the blocks from the belts 11, 12 until they are withdrawn at right angles to their original axis of movement by frictional contact with the belts 37, 38 moving immediately beneath `the plates 39.

Y The belts 37, 38 form an edge cleaning and groove edge coating section, indicated at 40 which is approximately twelve feet long, the speed of the belts 37, 38 being such as to provide a traverse time of about seven seconds. While moving along the belts 37, 38, the wood blocks are first engaged by motor driven rotary wire brushes 41 rotatable on vertical axes and positioned to clean extraneous Yfiller from the groove edges of the wood blocks 10, `which flowed onto the edges from the top surfaces during the padding stage, andare then engaged by vertical coating rollers 42 for coating the groove :edges of the wood blocks 10 with a top `coat composition.`

'Ifhe top coat composition, which is the final coating applied to the edges, and subsequently to the upper surfaces of the blocks 10, is -a synthetic resin or mixtures thereof that will form a non-thermoplastic lm by oxidation or chemical reaction accelerated by proper catalysts and/or heat. The reactive resin mixture used in this process is formulated to producea ilm of extremely high solid content which is tough yet exible and will have maximum abrasion and chemical resistance.

A satisfactory top coat composition is as follows:

Y Percent by weight 40% soya-glycerol pythalate alkyd (solids) 25 vButylated urea formaldehyde resin- 25 Butyl alcohol v p l5 Xylol 35 Catalyst-3 to 6% toluene sulfonic acid, based on urea formaldehyde solid's,

At the end of the belts 37, 3 8, the Wood vblocks 10 again are transferred to endless conveyor belts 43 and -44 moving at right angels to the belts 37, 38, transfer plates 39 being also provided 'at the intersections of these belts. The wood blocks 10 on the conveyor belts 43, 44 lirst pass through a tongue edge coating section 45 which is about seventeen feet in length, the conveyor belts 43, 44 having a speed to provide a traverse time through the section 45 of about twenty-one seconds. Within the section 45, the blocks 10 pass before the discharge nozzles of four air brush spray guns. 46 disposed to deposit the pre` Viously mentioned top coat composition onto the tongue edges of the blocks 10. At the exit end of the section 45, the surface of the wood blocks 10 will have a temperature of about 90 F.

The blocks then enter a top coat application station 47 4having. a length of about fourteen feet and a traverse time of about fourteen seconds, wherein two longitudinally spaced coating cylinders `48, 49 apply the previously mentioned top coat composition to the upwardly facing surfaces of the blocks 10. A forced air exhaust 50 may be centrally located within the section 47 to vent this section.

The blocks 10 then pass through a flash and How-out section51having a forced air circulation chamber and an exhaust 52 for rapidly evaporating the top coat composition applied by the rolls 48, 49. The length of the flash andflow-out section may be about thirty-nine feet and have a traverse time of about forty-six seconds. Next the blocks 10 pass through a rst stage top coat drying oven 53, which is preferably a forced circulation hot air oven having a steam c'oil and fan unit 54 at the exit end and an oven exhaust 55 at the entrance end to providea gradual rise in the temperature of the surface of the wood blocks 10 from about 90 1F. at the entrance end to about F. at the exit end.

The wood blocks are then transferred to a pair of endless conveyor belts 56, 57 spaced laterally from the belts 4344 and extending in parallelism therewith, by transfer endless conveyor belts 58, 59 extending at right angles to the previously mentioned belts and having a length of about ten feet and a traverse time of about six seconds.

The blocks 10 on the belts 56, 57 then pass through two sucessive infra-red heat ovens 60 and 61 forming second and third stage top coat drying ovens. The rst infra-red oven 60 preferably has about 80 750 watt ceramic type infra-red generators, a length of about thirty-five feet, and a traverse time of about forty-five seconds so that the wood blocks will have a surface temperature of about F. at the exit end of the oven 60. The third stage oven 61 preferably has about 72 750 watt ceramic type infra-red generators, a length of about thirty-one feet, and a traverse time ofV about forty seconds, so that-the wood blocks 10 will have a surface temperature of about F. at the exit end of the oven 61.

The blocks .10 then pass through a cooling section 62 which isabout fifty-four feet in length and has a traverse time of about seventy seconds. The cooling section 62 has a plurality of fans 63 therein to provide forced air cooling, and provides an exit temperature for the Wood blocks of about 100 F. The blocks then pass through an inspection and grading section 64 and then to a packaging section 65 Where the blocks are stacked in cartons for delivery to the shipping department.

The schematic illustration of the finishing line in the drawings shows the various longitudinal and transverse sections of the finishing line as having a single pair of conveyor belts for each section, as for example the belts 11, 12 in the first section, for convenience of illustration and description. `It will be understood, however, that these sections may be made up of any desired number of sets of conveyor belts arranged in series to successively receive the Wood blocks 10, and where discrepancies in belt speeds occur for different stages in a given section in the Ispecific example herein set forth, this will be eifected in actual practice by such successive sets of belts.

In order to provide effective control of the heat output of the infra-red ovens 32, 60 and `61 for varyingheat output to suit different conditions, electric timer controls of conventional commercial form `are preferably provided for these ovens, which may take the form of 'timer switches which cycle in sixty seconds and are adjustable to vary the relation of on time to olf time during cycle so as to selectively cycle the infra-red lamps.

If it is desired to seal the entire block 10 against moisture, the wash coat sealer applicator roll 16 may be arranged to simultaneously apply Wash coat sealer also to the downwardly facing surfaces of the blocks 10. The edges of the blocks 10 are substantially coated with sealer which flows from the top surfaces of the blocks after passage through the sealer applicator section 14.

By this process of nishing wood flooring blocks, a highly satisfactory factory finish having a high gloss and good wearing qualities may be provided on wood blocks by a continuous finishing process involving a total finishing time of about l1 minutes 5 second-s over a finishing line having a total length of about 542 feet. Because no interruptions in the finishing procedure are required to provide for extensive air dryingperiods, there is no necessity to provide for the extensive storage space required for stacking the flooring in the practice of the previously discussed prior art process and substantial economies in the production of wood flooring blocks may therefore be realized.

While but one embodiment of the invention has been particularly shown and described, it is apparent that various modifications may be made in the invention without departing from the spirit and scope thereof, and it is desired, therefore, that only such limitations shall be placed thereon as are set forth in the appended claims.

What is claimed is:

1. An integral and continuous process of factory nishing wood flooring to provide a composite type factory finish thereon wherein ooring units are continuously transferred along a production vline and the entire composite finishing operation is completed in a period of about eleven minutes comprising the successive steps of applying to the surfaces of the units to be nished a volatile, penetrating type of wash coat sealer composition which provides an adhesive platform for further finishing through penetration of the wood substratum and improves moisture and cold check resistance, drying the sealer coating with hot air under forced circulation for a period of about 65 seconds, sanding the dried sealer coating, cooling the sealer coating for a period of about 50 seconds, applying a volatile filler composition to the sealer coated surfaces to fill the open grain of the wood surfaces, padding and brushing the filler coating while it is still uid to distribute the same evenly over the coated surfaces and remove surplus filler, drying the filler coating by infra-red radiations for a period of about 44 seconds, cooling the filler coating for a period of about 33 seconds, polishing the ller coated surfaces with a high speed abrasive surface to eliminate raised nibs and surface aggravations, brushing said surfaces to clean them, then applying to said surfaces a top coating of heat convertible synthetic resin coat composition which forms an abrasion resistant and chemical resistant resin film thereon, and drying the top coat through a plurality of successive heating stages, at least one of said heating stages including heating of the top coat by infra-red radiation.

2. An integral and continuous process of factory finishing wood flooring to provide a composite type factory finish thereon blocks and the like wherein the flooring blocks are conveyed continuously along a production line, comprising processing the blocks in three successive and uninterrupted stages; the first stage including the successive steps of applying to the upwardly facing surfaces of the blocks a volatile penetrating type of wash coat sealer composition providing an adhesive platform for further finishing through penetration of the wood substratum and improving moisture and cold check resistance, flashing the sealer coating at substantially ambient temperature to produce rapid evaporation, drying the sealer coating with Vhot air under forced circulation, sanding the dried sealer coating, cooling the sealer coating, said first stage involving a period of about two to three minutes; the second stage including` applying a volatile filler composition to said upwardly facing surfaces to fill the open grain of the wood surfaces, padding and brushing the filler coating while it is still fluid to distribute the same evenly over said surfaces and remove surplus filler, drying the filler coating by heating the same with infra-red radiation, then cooling the filler coating, polishing the filler coated surfaces under light and uniform pressure with a resiliently backed polishing sheet faced with abrasive particles to embed raised nibs into the wood and eliminate surface aggravations, brushing said surfaces to clean them,rsaid second stage involving a period of about two to three minutes; the third stage involving a period of about five to six minutes and including applying to said surfaces a coating of heat convertible synthetic resin which can be cured in about four to five minutes as a top coat composition which forms an abrasion resistant and chemical resistant film thereon, and drying thetop coat through a plurality of successive heating stages including first hot air forced circulation heating stage and at least one succeeding infra-red radiation heating stage.

3. An integral and continuous process of factory finishing rectangular wood flooring blocks having tongueA and groove edges to provide a composite type factory finish on said blocks in an uninterrupted series of successive operations while the flooring blocks are conveyed continuously along a production line and the entire composite finishing operation is completed in about eleven minutes, comprising the successive steps of applying to the upwardly facing surfaces of the blocks a volatile penetrating type of wash coat sealer composition providing an adhesive platform for further finishing through penetration of the wood substratum and improving moisture and cold check resistance, flashing the sealer coating at substantially ambient temperature to produce rapid evaporation for a period of about five seconds, drying the sealer coating with hot air under forced circulation for a period of about 65 seconds, sanding the dried sealer coating, cooling the sealer coating for a period of about 50 seconds, applying a volatile filler composition to said upwardly facing surfaces to fill the open grain of the wood surfaces, padding and brushing the filler coating while it is still fiuid to distribute the same evenly over said surfaces and remove surplus filler, drying the filler coating by heating the same with infra-red radiation for a period of about 44 seconds, then cooling the filler coating for a period of about 33 seconds, polishing the filler coated surfaces under light and uniform pressure with a resiliently backed polishing sheet faced with abrasive particles to embed raised nibs into the wood and eliminate surface aggravations, brushing said surfaces to clean them, brushing the groove edges of the blocks to remove excessive ller from them, applying a resin top coat composition to said groove edges, spraying a resin top coat composition to the tongue edges of said blocks, applying to said upwardly facing surfaces a coating of heat convertible synthetic resin as atop coat composition which forms an abrasion resistant and chemical resistant film thereon, and drying the top coat through a plurality `of successive heating stages including first hot air forced circulation heating stage and two successive. infra-red radiation heating stages, the rst of said lastmentioned infra-red heating stages being for a period of about 45 seconds and the second for a period of about 40 seconds.

4. An integral and continuous process of factory finishing wood flooring blocks and the like to provide a composite type factory finish thereon wherein the flooring 'blocks are conveyed continuously along a production line, comprising the successive steps of applying to the upwardly facing surfaces of the blocks a volatile penetrating type of wash coat sealer composition of a lacquer type material having a Vinyl resin base dissolved in organic solvents providing an adhesive platform for further finishing through penetration of the wood substratum and improving moisture and cold check resistance, drying the sealer coating with hot air under forced circulation raising the temperature of the coating to about 110 F., sanding the dried sealer coating, cooling the sealer coating to about F., applying -a volatile filler coating of a urea formaldehyde resin base composition which includes inert filling pigments, organic and inorganic pigments, and organic dye-stuffs to Said upwardly facing surfaces to fill the open grain of the wood surfaces, padding and brushing the filler coating while it is still fluid to distribute the same evenly over said surfaces and remove surplus filler, drying the filler coating -by heating the same with infra-red radiation to a temperature of about 135 F., then cooling the filler coating to about F., polishing the filler coated surfaces under light and uniform pressure with a resiliently backed polishing sheet faced with abrasive particles to embed raised nibs into the wood and eliminate surface aggravations, brushing said surfaces to clean them, applying to said upwardly facing surfaces a top coat of a butylated urea formaldehyde resin base composition which forms an abrasion resistant and chemical resistant film thereon, and heating the top coat to dry the Same 9 through a plurality of heating stages including a rst heating stage to about 95 F., then a second heating stage to about 115 F., then -a third heating stage to about 135 F., said second and third stages being infra-red radiation heating stages.

5. The method of claim 1, in which the wash coat sealer composition is a lacquer type material having a vinyl resin base dissolved in organic solvents, the filler composition is a urea formaldehyde resin base composition and includes inert filling pigments, organic and inorganic pigments, and organic dye-stuffs, and the top coat composition is a butylated urea formaldehyde resin base composition.

6. Apparatus for finishing wood -ooring forming an integral Iand continuous processing line therefor to provide a composite type factory finish on the flooring comprising means for applying to the upper surface of the Wood flooring a volatile, penetrating type of wash coat sealer composition, hot air forced circulation oven means for heating the sealer coating to dry the same, sanding means adjacent the exit end of said oven for sanding the sealer coated surfaces of the flooring, a cooling stage for cooling the sealer coating, a filler applicator for applying a volatile filler composition to the sealer coated diooring surfaces to till the open grain of the surfaces, a plurality of padders for distributing the iiller coating uniformly over the flooring surfaces, brush cylinder means for removing surplus filler from the flooring surfaces and cleaning the surfaces, a drying oven including an elongated Iseries of infra-red generators for rapidly drying the filler coating, a cooling stage adjacent the exit end of said infra-red oven for cooling said filler coating under forced circulation, means for polishing the ller coated surfaces including a fine grit abrasive belt applied to said ooring surfaces under light uniform pressure for eliminatng raised nibs and surface aggravations, brush means for removing surface dust from said floor-ing surfaces, applicator means for applying to -said surfaces a top coat resin composition forming an abrasion resistant and chemical resistant film thereon, a plurality of drying ovens for heating the top coat coated surfaces through a plurality of gradual temperature increments, at least one of said last mentioned ovens including an elongated series of infra-red generators and a conveyor for conveying the dooring past the Kaforesaid instrumentalities in the order stated.

7. Apparatus for nishing wood flooring forming an integral and continuous processing line therefor to provide a composite type factory finish on the ooring comprising means for applying to the rupper surface o-f the Wood ooring Ia volatile, penetrating type of wash coat sealer composition, hot air forced circulation oven means for heating the sealer coated surfaces to about 110 F. to dry the same, sanding means adjacent the exit end of said oven for sanding the sealer coated surfaces of the flooring, a cooling stage for cooling the sealer coating to about 85 F., a filler applicator for applying a volatile filler composition to the sealer coated flooring surfaces to ll the open grain of the surfaces, a plurality of padders for distributing the filler coating uniformly over the flooring surfaces, brush cylinder means for removing surplus filler from the ooring surfaces and cleaning the surfaces, -a drying oven including an elongated series of infra-red generators for rapidly drying the filler coating by heating the same to about 135 F., a cooling stage adjacent the exit end of said infra-fred oven for cooling said filler coating under forced circulation to about 100 F., means for polishing the filler coated lsurfaces including a line grit abrasive belt applied to said flooring surfaces under light uniform pressure for eliminating raised nibs and surface aggravations, brush means for removing surface dust from said flooring surfaces, applicator means for applying to said surfaces a top coat resin composition forming an 4abrasion resistant and chemical resistant film thereon, means for dashing and owing-out the top coat under forced circulation to produce rapid evaporation, a hot air forced circulation drying oven for heating Said top coated surface to a temperature of about F., a first infra-red top coat drying oven for heating the top coated 'surface to a temperature of about 115 F. and a second infra-red top coat drying oven for further raising the temperature of the top coated surface to about 135 F., means for cooling the top coat to a temperature of about F., and a conveyor for conveying the flooring past the aforesaid instrumentalities in the order stated.

8. An integral and continuous process of factory finishing rectangular Wood ilooring blocks to provide a composite type factory finish on said blocks in an uninterrupted series of successive operations while the ooring blocks are conveyed continuously along a production line and the entire composite finishing operation is completed in about eleven minutes, comprising the successive steps of applying to the upwardly facing surfaces of the blocks a volatile pentrating type of wash coat sealer composition providing an adhesive platform for further finishing through penetration of the wood substratum and improving moisture and cold check resistance, ashing the sealer coating at substantially ambient temperature to produce rapid evaporation for a period of about five seconds, drying the sealer coating with hot air und-er forced circulation for a period of about 65 seconds, applying a volatile filler composition to said upwardly facing surfaces to fill the open grain of lthe wood surfaces, padding and brushing the filler coating while it is still duid to distribute the same evenly over said surfaces and remove surplus filler, drying the filler coating by heating the same with infraared radiation for a period of about 44 seconds, then cooling the filler coating for a period of about 33 seconds, polishing the filler coated surfaces -under light and uniform pressure with a resiliently backed polishing sheet faced with abrasive particles to embed raised nibs into the wood and eliminate surface raggravations, brushing said surfaces to clean them, applying to said upwardly facing surfaces a coating of heat convertible synthetic resin as a top coat composition which forms an abrasion resistant and chemical resistant film thereon, and drying the top coat through a plurality of successive heating stages including first hot air forced circulation heating stage and two successive infra-red radiation heating stages, the first of said last-mentioned infra-red heating stages being for a period of about 45 seconds and the second for a period of `about 40 seconds.

References Cited in the file of this patent UNITED STATES PATENTS 2,341,161 Par-tee et al. Feb. 8, 1944 2,450,681 Muench Oct. 5, 1948 2,772,986 Buck Dec. 4, 1956 

1. AN INTEGRAL AND CONTINUOUS PROCESS OF FACTORY FINISHING WOOD FLOORING TO PROVIDE A COMPOSITE TYPE FACTORY FINISH THEREON WHEREIN FLOORING UNITS ARE CONTINUOUSLY TRANSFERRED ALONG A PRODUCTION LINE AND THE ENTIRE COMPOSITE FINISHING OPERATION IS COMPLETED IN A PERIOD OF ABOUT ELEVEN MINUTES COMPRISING THE SUCCESSIVE STEPS OF APPLYING TO THE SURFACES OF THE UNITS TO BE FINISHED A VOLATILE, PENETRATING TYPE OF WASH COAT SEALER COMPOSITION WHICH PROVIDES AN ADHESIVE PLATFORM FOR FURTHER FINISHING THROUGH PENETRATING OF THE WOOD SUBSTRATUM AND IMPROVES MOISTURE AND COLD CHECK RESISTANCE, DRYING THE SEALER COATING WITH HOT AIR UNDER FORCED CIRCULATION FOR A PERIOD OF ABOUT 65 SECONDS, SANDING THE DRIED SEALER COATING, COOLING THE SEALER COATING FOR A PERIOD OF ABOUT 50 SECONDS, APPLYING A VOLATILE FILLER COMPOSITION TO THE SEALER COATED SURFACES TO FILL THE OPEN GRAIN OF THE WOOD SURFACES, PADDING AND BRUSHING THE FILLER COATING WHILE IT IS STILL FLUID TO DISTRIBUTE THE SAME EVENLY OVER THE COATED SURFACES AND REMOVE SURPLUS FILLER, DRYING THE FILLER COATING BY INFRA-RED RADIATIONS FOR A PERIOD OF ABOUT 44 SECONDS, COOLING THE FILLER COATING FOR A PERIOD OF ABOUT 33 SECONDS, POLISHING THE FILLER COATED SURFACES WITH A HIGH SPEED ABRASIVE SURFACE TO ELIMINATE RAISED NIBS AND SURFACE AGGRAVATIONS, BRUSHING SAID SURFACES TO CLEAN THEM, THEN APPLYING TO SAID SURFACES A TOP COATING OF HEAT CONVERTIBLE SYNTHETIC RESIN COAT COMPOSITION WHICH FORMS AN ABRASION RESISTANT AND CHEMICAL RESISTANT RESIN FILM THEEON, AND DRYING THE TOP COAT THROUGH A PLURALITY OF SUCCESSIVE HEATING STAGES, AT LEAST ONE OF SAID HEATING STAGES INCLUDING HEATING OF THE TOP COAT BY INFRA-RED RADIATION. 